As legalization and medical marijuana become increasingly adopted by the states, prohibitionists are desperate to document how this has been a public policy disaster.

The problem is that all their predictions about how legalization would usher in a pot apocalypse have failed to come true. They thought that certainly, as marijuana became more accessible and acceptable, more teenagers would fall into the clutches of the demon reefer.

“We had predicted based on the changes in legalization, culture in the U.S. as well as decreasing perceptions among teenagers that marijuana was harmful that [accessibility and use] would go up. But it hasn’t gone up,” explained Dr. Nora Volkow, the director of the National Institute on Drug Abuse (NIDA), to US News & World Report.

Indeed, the annual Monitoring the Future survey commissioned by NIDA has found that nationally, marijuana use and accessibility have decreased among teenagers.

“We’re seeing that more people in the U.S. except for teenagers are taking it,” Volkow said. “The rates of increases are highest among young adults 18-24, so one would expect that would translate to the adolescents, but apparently it has not. I don’t have an explanation. This is somewhat surprising.”

(Monitoring the Future has been surveying 12th graders since 1975; its survey of 8th and 10th graders dates back to 1991, so our discussion will only include data from 1991 forward, unless otherwise noted.)

In 1991, the “perception of risk of harm [due to] regular marijuana smoking” was at the highest levels recorded for all grades—84 percent for 8th graders, 82 percent for 10th graders and 79 percent for 12th graders. In 1992 and 1993, that perception began decreasing, but still those years placed with in the top five for most perception of harm.

Also in 1991, the “disapproval of regular marijuana smoking” was at the highest levels recorded—92 percent among 8th graders, 90 percent among 10th and 12th graders.

Then in 1992, a sax-playing womanizer who claimed he “didn’t inhale” was elected president. The medical marijuana era began in earnest as California ratcheted up the successful campaign for Proposition 215.

As prohibitionists predicted, teen perception of harm and disapproval plummeted. By 1999, 8th grade harm perception fell over 10 points; 10th grade saw a 16-point drop; and high school seniors’ perception that regular marijuana use was harmful had dropped 21 points. Disapproval of regular use dropped similarly, falling almost 8 points in 8th grade, 10 points in 10th grade and 11 points in 12th grade.

Sure enough, teen use skyrocketed in that era. By 1996 and 1997, the teens that had just five years earlier posted the lowest recorded monthly marijuana use rates ever were posting the highest recorded marijuana use rates ever. Among the 10th and 12th graders, use about doubled, while among 8th graders, it more than tripled.

It’s easy to understand how the prohibitionists who emerged from the dawn of the medical marijuana era would translate these trends into two equations:

#1 – less fear plus less disapproval equals more use;

#2 – more legalization plus more acceptance equals more use.

But over the past decade, the data has destroyed those two equations, and now the prohibitionists don’t know what to think.

Since 2007, prior to the expansion of the medical marijuana industry and the adoption of recreational legalization, we have seen the teen perception of risk and disapproval of regular marijuana use fall to the lowest levels ever recorded. In fact, the last six years have seen the five lowest measurements ever recorded.

But the teen use of marijuana is falling for grades 8 and 10 and remaining steady for grade 12. Last year’s 8th grade use rate was the lowest recorded since 1993. Tenth grade use hasn’t been this low since 2008, and before that, a rate this low hadn’t been seen since 1993. Only 12th grade use remains above average, still at a rate similar to the late 1990s.

As for access, marijuana is harder than ever for teens to acquire.

At the peak in the late 1990s, over half of 8th graders, over 80 percent of 10th graders and over 90 percent of 12th graders said marijuana was “easy or fairly easy” to acquire. Today, a little over a third of 8th graders, a little under two-thirds of 10th graders and just over 80 percent of 12th graders say the same.

So why did a decrease in teen risk perception and disapproval correlate with a rise in teen use and access in the 1990s, but a far greater drop in risk perception and disapproval have led to lower teen use and access in the 2010s?

Simple. Teen risk perception isn’t decreasing, so much as it is becoming accurate.

Think about the messages teens received about marijuana back in the 1990s from the government and media. It’s a deadly gateway drug that leads straight to heroin and smashing up your kitchen with a frying pan! It’s going to make you a lazy, unmotivated failure in life! Your girlfriend will leave you for a cartoon alien! Your talking dog will disapprove of you! The only people who use it are degenerate criminal addict losers!

Then, think about the realities teens saw over the past two decades. It’s a healing natural drug that leads straight to people with cancer who are busy in the kitchen feeding their new appetite! It’s made thousands of medical marijuana patients productive in life! Your girlfriend is much nicer when she tokes to treat her menstrual cramps! Your dog’s arthritis is alleviated by CBD treats! The people who use it are no longer criminals!

Any measure we take of marijuana—whether it is perception of risk, disapproval of use, accidental child/pet ingestions, instances of cannabinoid hyperemesis syndrome, number of stoned drivers and even admitted use itself—is confounded by the prohibition that demonizes marijuana and its users and incentivizes them to lie.